• Journal of the Optical Society of Korea
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• 제12권1호
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• pp.42-48
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• 2008

The relative intensity noise (RIN) characteristics in 405 nm blue laser diodes grown on wurtzite AlGaInN multiple quantum well structures were investigated using the rate equations with the quantum Langevin noise model. The device parameters were extracted from the optical gain properties of the MQW active region using the self-consistent numerical method developed for calculating the multiband Hamiltonian in the strained wurtzite crystal. These methods have been applied to laser diodes for various conditions including the external feedback and the high frequency current injection.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.119-122
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• 2003

This paper describes the sensorless technique for the surface-mounted permanent-magent synchronous motor(SPMSM or PMSM) drive based on magnetic saliency. The control technique is a sensorless control algorithm that injects the high frequency voltage to the stator terminal in order to estimate the rotor position and speed. The rotor position and speed for sensorless vector control is achieved by appropriate signal processing to extract the position information from the stator current in the low speed range including zero speed. Proposed sensorless algorithm using the double-band hysteresis controller and initial rotor position detection exhibits excellent reference tracking and increased robustness. Experimental results are presented to verify the feasibility of the proposed control schemes.

• Journal of Power Electronics
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• 제19권4호
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• pp.956-967
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• 2019

This paper introduces a virtual signal injected maximum torque per ampere (MTPA) control strategy for direct-torque-controlled five-phase interior permanent magnet synchronous motor (IPMSM) drives. The key of the proposed method is that a high frequency signal is injected virtually into the stator flux linkage. Then the responding stator current is calculated and regulated to compensate the amplitude of the flux linkage. This is done according to the relationship between the stator current and the stator flux linkage. Since the proposed method does not inject any real signals into the motor, it does not cause any of the problems associated with high-frequency signals, such as additional copper loss and extra torque ripple. Simulation and experimental results are offered to verify the effectiveness of the proposed method.

• 전력전자학회논문지
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• 제27권1호
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• pp.80-83
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• 2022

This paper proposes an initial rotor polarity detection algorithm of a single-phase permanent magnet synchronous motor (SP-PMSM) related to stable open-loop starting for sensorless operation. Generally, the SP-PMSM needs an asymmetric air-gap structure to can avoid the initial starting failure at zero torque point. Therefore, the rotor polarity information can be obtained by using the DC offset current direction of a stator current through a high frequency voltage injection into an SP-PMSM with an asymmetric air gap. In this paper, the proposed rotor initial polarity detection algorithm is verified through several experimental results.

• 한국연소학회지
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• 제3권1호
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• pp.59-69
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• 1998

The results of study on the active control of naturally occurring combustion oscillations with a single dominant frequency in an atmospheric dump combustor are presented. Control was achieved by an oscillatory infection of secondary fuel at the dump plane. A high speed solenoid valve with a maximum frequency of 250Hz was used as the actuator and a sound level meter, located at the combustor exit, measured the pressure fluctuations which served as the feedback signal for the control loop. Instability characteristics were mapped over a range of mean mixing section velocities from 6.7 m/s-9.3 m/s and with three mixing conditions. Different fuel/air mixing conditions were investigated by introducing varying percentages of primary fuel at two locations, one at the entrance to the mixing section and one 6 mixing tube diameters upstream of the dump plane. Control studies were conducted at a mean velocity of 9.3 m/s, with an air temperature of $415^{\circ}C$, and from flame blowout to the stoichiometric condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.217-219
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• 2005

To detect partial discharge of 154kV joint box, we have made experiment by using the HFCT sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we test reliability on both injection of calibration signal in NJB and removal of low frequency. After that, we had analyzed frequencies by measuring signals in IJB with 300[m] distance from NJB. Also we had measured S/N ratio by using the indirected injection method of calibration signal in IJB. In this experiment, two measurement methods were difference of detection acquisition, but these had the equal frequency properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기설비전문위원
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• pp.75-78
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• 2007

To detect partial discharge of 154kV joint box, we have made experiment by using the HFCT sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we test reliability on both injection of calibration signal in NJB and removal of low frequency. After that, we had analyzed frequencies by measuring signals in IJB with 300[m] distance from NJB. Also we had measured S/N ratio by using the indirected injection method of calibration signal in IJB. In this experiment, two measurement methods were difference of detection acquisition, but these had the equal frequency properties.

• Journal of Forest and Environmental Science
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• 제34권5호
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• pp.376-381
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• 2018

For the control of oak wilt caused by Raffaelea quercus-mongolicae, an antifungal microorganism, Streptomyces blastmyceticus, was used as a potential agent. Culture suspension of S. blastmyceticus was injected into Quercus mongolicae in the research forest of Kangwon National University by $ChemJet^{(R)}$ trunk injection and Macro-infusion at root flare injection. $Alamo^{(R)}$ (a.i., propiconazole 14.5%), a fungicide currently used for the control of oak wilt in USA, was also treated by both methods to compare the efficacy. For preventive efficacy, culture suspension of the pathogen was inoculated at 1 month after injection of either agent. Tested trees were cut at 3 months after treatment, stained with 1% Fuchsin acid, and then non-conductive area (NCA) and re-isolation frequency (RIF) of oak wilt fungus were compared among treatments. While NCA was the highest as 47.3% in pathogen only treatment, it was the lowest as 16.0% in sterilized water treatment by Macro-infusion. NCAs of Alamo treatment by Macro-infusion and ChemJet injection were 25.3% and 32.1%, respectively. NCA of S.blastmyceticus treatment by ChemJet injection was 32.3%, similar with Alamo treatment's by ChemJet injection. All treatments by either injection method showed significantly lower NCA compared to the pathogen only treatment. These results indicate that S. blastmyceticus injection shows the preventive efficacy against oak wilt disease by suppressing the growth of pathogen injected. NCA of Macro-infusion injection of sterilized water was lower as 16.0%, compared to 21.3% of ChemJet injection. It means that Macro-infusion is more effective in translocation of sterilized water than ChemJet injection by even distribution. RIF from wood discs of treated trees showed high in pathogen only treatment, but relatively low in S. blastmyceticus treatment. RIF results were correlated with NCA results. From the above results, it was confirmed that S. blastmyceticus showed preventive efficacy against oak wilt disease by ChemJet trunk or Macro-infusion at root flare injection.

• 치위생과학회지
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• 제5권2호
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• pp.51-56
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• 2005

이 연구는 치과진료에서 처방되는 약제를 분석함으로써 해당 치과병 의원의 정보 자료의 제공 등으로 자율적 개선 노력 유도 및 지속적인 처방행태 변화추이 공개로 적정처방 및 벤 치마킹유도와 국민에게 항생제, 주사제 등의 약제 사용실태 홍보로 적정 약제 사용을 위한 인식 변화 유도에 기여하고자 이 연구를 시행하였다. 2003년 7월 1일부터 9월 31일까지 요양기관 34,226개소의 건강보험 외래약제 처방내역을 이용하여 항생제, 주사제의 투약일수율 및 처방률, 투약일당 약품비, 처방건당 약품목수와 고가약품목수의 비중에 대해 분석한 결과 다음과 같은 결론을 얻었다. 1. 항생제에 대한 투약일수율은 치과의원이 90.11%로 전년 동기 및 전분기보다 낮게 나타났으나, 처방률은 15.50%로 전년 동기 및 전분기보다 높게 나타났다. 치과병원의 투약일수율과 처방율은 각각 71.57%와 21.05%로 전분기보다 다소 높게 나타났다. 타종별 요양기관보다는 치과 병 의원의 투약일수율은 매우 높으나 처방률은 낮게 나타났다. 2. 주사제에 대한 투약일수율과 처방률은 치과의원이 각각 0.13%과 0.05%로 전년 동기보다는 감소추세로 나타났으며, 치과병원의 투약일수율과 처방률도 각각 1.03%과 0.88%로 전분기보다 다소 낮게 나타났다. 타 요양기관 종별보다는 치과병 의원의 주사제 투약일수율과 처방률은 매우 낮은 것으로 나타났다. 3. 약품목수는 치과의원이 2.79개로 전년 동기보다는 낮아졌으나 전분기보다는 높게 나타났으며, 치과병원은 2.67개로 전년 동기 및 전분기에 비해 증가된 것으로 나타났다. 타종별 요양기관보다는 치과병 의원 모두 약품목수가 적은 것으로 나타났다. 4. 투약일당 약품비는 치과의원이 863원으로 전년 동기 및 전분기에 비해 증가추세로 나타났으며, 치과병원은 1,385원로 전분기보다 낮게 나타났다. 타종별 요양기관보다는 치과병 의원 모두 낮은 것으로 나타났다. 5. 고가약품목수 비중은 치과의원이 46.43%로 전분기보다 높게 나타났으며, 치과병원은 54.05%로 전분기보다 매우 높게 나타났다. 병 의원에 비해 치과병 의원이 고가약품 목수 비중이 높은 것으로 나타났다. 6. 지역별 외래처방 현황 분석시 항생제 처방률은 광주지역이 가장 높고 대전지역이 가장 낮은 것으로 나타났으며, 주사제 처방률은 2/4분기 결과와 마찬가지로 영남지역이 모두 높은 반면, 수도권 지역은 모두 낮은 처방률로 나타났으며, 지역별 변이도 매우 커 최대지역의 처방률이 최소지역의 처방률의 2배 이상 높은 것으로 나타났다. 투약일당 약품비는 울산지역이 가장 높고 전북지역이 가장 낮게 나타나며, 처방건당 약품목수는 경기지역이 가장 높고 제주지역이 가장 낮게 나타났다.

• 정보보호학회논문지
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• 제24권3호
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• pp.453-460
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• 2014

오류주입공격(Fault Injection Attack)은 하드웨어적 또는 소프트웨어적으로 구현된 암호칩에 인위적으로 오류를 주입 또는 발생시켜 암호 알고리즘 동작/수행을 방해함으로써 칩에 내장된 정보를 찾아내는 공격으로, 이 중 레이저를 이용한 오류주입공격은 특히 성공적인 것으로 입증된 바 있다. 본 논문에서는 기존의 플래쉬 펌프 방식의 레이저와 광섬유 레이저 모델을 병렬 결합한 이중모드 레이저 방식으로 개선된 레이저 프루빙 시스템을 제안하였다. 제안된 방법은 에너지 출력은 높으나 주파수 반복률이 낮아 오류주입공격 실험에 적합하지 않은 기존의 플래쉬 펌프 방식 레이저를 레이저 절단용으로 활용하고, 추가로 별도의 오류주입을 위한 고주파 반복률을 갖는 레이저를 단순 병렬 결합시키는 방법이다. 오류주입을 위해 결합된 제 2의 신규 레이저는 반도체 레이저와 광섬유 레이저를 선택하여 두 가지 시스템을 설계하였으며, 이에 따른 장 단점을 비교분석하였다.